Selecting a Depth Gauge on Amazon.com

A depth gauge, or depth gage, is a precision instrument for measuring the depth of a hole, slot, step, or other recess in manufacturing, machining, and mechanical engineering applications. It usually consists of a rod or ruler that extends from a T-bar base that spans the recess. Readings are displayed on a dial indicator, a graduated scale, an analog counter, or a digital readout. A depth gauge that has a micrometer head is also known as a depth micrometer. Certain depth gauges are designed specifically for measuring tire tread. To ensure the accuracy of a depth gauge, it may be checked against a gage block and surface plate. A digital depth gauge may have an output port for connecting to a computer to collect data. Depth gauges vary as to their measuring range, accuracy, and resolution. Some include interchangeable rods to allow a wide range of measurement. They may be manufactured to standards such as Ingress Protection (IP), Deutsches Institut für Normung (DIN), and Norme Française (NF), and may include a National Institute of Standards and Technology (NIST) calibration certificate.